Task data: m (lead mass) = 15 kg; t0 (temperature at which the lead was located) = 27 ºС.
Reference values: by condition C (specific heat of lead) = 0.126 kJ / (kg * k) = 126 J / (kg * K); λ (heat of fusion) = 21 kJ / kg = 21000 J / kg; t (melting point) = 327 ºС.
The amount of heat for melting 15 kg of lead is calculated by the formula: Q = Qn + Qpl = C * m * (t – t0) + λ * m = m * (C * (t – t0) + λ).
Calculation: Q = 15 * (126 * (327 – 27) + 21000) = 882,000 J (882 kJ).
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